Engine timing device



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ENGINE TIMING DEVICE Filed March 3, 1954 2 Sheets-Sheet l m mg INVENTOR. Dfi /D 5. #00655 w I mvn HTTOENEYS A 1 a v D/lzlywl 1335 D g HQDGES ENGINE TIMING DEVICE 2 Sheets-Sheet 2 Filed March 3, 1954 I IN V EN TOR. D19 V/D 5. H0065? AND United States PatentO ENGINE TIMING DEVICE David B. Hodges, San Antonio, Tex.

Application March 3, 1954, Serial No. 413,979

6 Claims. (Cl. 116-124) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the United States Government for governmental purposes without payment to me of any royalty thereon.

This invention relates to an improved timing disc for use in checking valve clearance and fuel injection timing of aircraft engines using low tension magnetos.

In checking the valves of an aircraft engine it is customary to remove two bolts from the magneto housing and bolt a timing disc to the housing therewith, then remove a cap screw from the end of the magneto shaft and attach a pointer thereto for rotation therewith and use in conjunction with the timing disc to time the engine. With the present invention this procedure is simplified by using a flanged mounting assembly that slips over the magneto housing with an easy motion and is frictionally clamped thereto for fixed relation to the magneto housing. This assembly serves to mount a reference pointer. Journalled in the mounting assembly is a spindle having a hexagonal socket at the inner end for engagement with the magneto shaft which spindle is of reduced diameter at its other end and threaded to receive a timing disc fixed for rotation with the spindle relative to the reference pointer by a wing nut. The timing disc is inscribed at the proper points on its periphery with the check positions for a given engine in degrees during a cycle so correct valve clearance, magneto and fuel injection timing may be accurately provided. This simple and novel timing disc assembly of this invention as will be readily seen provides a ready check of proper adjustment of the essential elements whereby a highly accurate timing of an engine may obtain.

An object of the invention is to provide a highly simplified timing apparatus for an engine where access to the engine crankshaft is not readily available.

A further object of the invention is to provide a timing apparatus for use with a magneto of an engine which may be applied to the magneto without necessity of extensive disassembly of the magneto housing.

An additional object of the invention is to provide a timing assembly for an engine which may be applied by merely slipping the assembly over a magneto housing and clamping it thereto which device includes means for engagement and rotation with the magneto shaft to give a transmission of engine crankshaft position.

Other objects and advantages of the invention will become readily apparent to those versed in the art from the following description taken .in conjunction with the accompanying drawings wherein:

Fig. l is a plan view of the timing apparatus assembly.

Fig. 2 is a partial cross-section showing the assembly details.

Fig. 3 is a perspective of the retainer elements.

Fig. 4 shows the timing disc as inscribed for use with a particular engine.

As can be seen, particularly with reference to Fig. 2 of the drawings, the assembly of the invention is composed of fixed and relatively movable elements. The fixed portions consist of a base plate 1 having retainer or adapter elements 2 secured thereto by screws extending through the flanged portions 3 of the retainer elements into the base member. The main retainer portions 4 of the adapter elements are curved in nature as can be readily seen with reference to Fig. 3 of the drawings. A pressure plate assembly 5, composed of a ring member 6 having offset bolt members 7 each at one end thereof welded to one and the same side of ring member 6 and diametrically opposed and each having outwardly extending threaded portions at the other ends thereof, is connected to the adapter members by the members 7 which extend outwardly through the openings 8 in the symmetrically arranged retainer portions 4 of the adapters 2. Reinforcing elements or plates 9 fit over each threaded oflfset member to abut the retainer members. Wing nuts 10 on the threaded portions of offset members 7 are adjustable to apply pressure through plates 9 to the retainer members to vary the clamping effect thereof. Journalled in and extending through the base member 1 is a spindle 11 having a flange 12 abutting the base disc at the outer side thereof. A collar 13 about the spindle at the inner side of the base disc is clamped to the spindle by a screw and prevents axial displacement of the .spindle relative to the base disc. The spindle 11 at its outer end is reduced in diameter. Loosely fitted about the flange 12 on the spindle is a ring member 14 having an ami 15 extending outwardly therefrom, the outer end of the arm having a reentrant flange portion 16 that engages the under side of the base disc which the ring member abuts. A pointer reference element 17 is welded to the outer side of the arm 15 adjacent the periphery of the base disc. The pointer element and the arm have threaded openings therethrough which are engaged by a screw member 18 which can fix the pointer element relative to the base disc .in any desired reference position. A timing disc 19 is mounted on the spindle at its reduced portion abutting the flange 12 thereof outwardly of arm 15 and has one edge thereof underlying the reference pointer 17. A gasket 20 and a washer 21 on the spindle are held in abutting relation to the timing disc by a wing nut 22 threadedly engaging the outward end of the spindle clamping the disc for rotation with the spindle. The inner end of the spindle has a hexagonal head for purposes to be described herein. The outer face of the timing disc is calibrated and inscribed in degrees to establish the required check positions of an engine crankshaft in a particular engine during a complete cycle of an engine so that reference pointsare readily available at which the valve clearance and magneto and fuel injection timing may be checked.

The particular novel structure of the invention is very simple and its application and advantages are readily apparent. In application the timing may be accomplished through a magneto or similar auxiliary drive where direct access to an engine crankshaft is unavailable.

In the example shown the retainer elements 2 are arranged to slip over a magneto housing in clamping engagement therewith with the inner end of the spindle engaging the magneto shaft by its socket portion for driven engagement therewith. The nuts 10 are then adjusted to clamp the retainer elements against the magneto housing to hold the base disc in fixed relation thereto. The engine is then set to provide the first check point or first cylinder piston at T. D. C. so that the timing disc and the associated pointer may be initially referenced. Once the drive shaft and connected spindle are properly positioned, the reference pointer may be clamped to the base disc in a position where it is visible and the timing disc adjusted to zero with the pointer in the initial visible position. Then as the engine crankshaft is rotated the positions of the check points for the valves and magneto and fuel ignition timing are clearly read on the timing disc, which is inscribed for 3 check points for the particular engine being tested in a manner such as shown in Fig. 4 of the drawings, as identified by the reference pointer and the valve clearance and magneto and fuel ignition timing may be readily checked and adjusted at these points in a highly accurate fashion. It is noted that the outer end of the spindle is hexagonal and provides a means of applying a torque wrench to take up back lash in engine gearing.

While a specific application and embodiment of the invention has been shown herein it is not to be construed as limiting but merely as an example since various modifications and applications of the invention will be readily apparent to those versed in the art. The invention .is intended to be limited only as defined by the claims.

What is claimed is:

1. A timing device for engines wherein the engine crankshaft is not readily accessible, for use in combination with a magneto, comprising adapter means to slip over a protruding, accessible end of the magneto housing and frictionally clamp to the side of the magneto housing, a mounting disc dependingly mounting the adapter means, biasing means operatively engaging said adapter means and adjustable to provide a tight frictional clamping engagement of the housing by the adapter means, a spindle journalled in said mounting disc having means at one end thereof for engagement of the magneto shaft for rotation therewith, a timing disc secured to the other end of the spindle for rotation therewith and having the check points of the engine inscribed thereon and a reference pointer means adjustably mounted on said mounting disc for home referencing relation relative to said timing disc whereby a quick and accurate check of engine timing may be made.

2. A timing device for engines for cooperation with a magneto comprising a mounting base member, resilient retainer elements dependingly mounted to said mounting base, a bias plate associated with the retainer elements, means interconnecting the bias plate and the retainer elemerits and adjustable to bias the retainer elements to afford a frictional clamping engagement with the sides of a magneto when mounted thereon, a spindle extending through said base member having means at the inner end thereof for operative engagement with the magneto shaft and rotation relative to said base member, a timing disc mounted on the other end of the spindle and secured thereto, a reference pointer adjustably mounted on said base member and adjustable to start indexing position relative to said timing disc, said reference pointer overlying the periphery of the timing disc for association therewith to indicate the appropriate engine check points in accordance with the rotation of the engine crankshaft.

3. A timing device for engines for association with an auxiliary drive and its housing where direct access to the engine crankshaft is not readily available comprising, a mounting base, clamping jaws dependingly secured to the mounting base means to bias the jaws into tight frictional engagement with the sides of the housing of the auxiliary drive, a spindle mounted in said mounting base arranged for rotation relative thereto, means at one end thereof for positive, direct interlocking engagement with the auxiliary drive for rotation therewith, a timing disc secured to the other end of the spindle, and a reference pointer connected to said base member and associated with said timing disc for quick and accurate engine timing.

4. A timing device for engines for use with a magneto where direct access to the engine crankshaft is not readily available comprising a mounting base for connection in fixed relation to the magneto housing, means secured to said mounting base for frictionally retaining said mounting base to the magneto housing, a spindle journalled in said mounting base having the inner end thereof adapted to engage the magneto shaft for rotation therewith, a timing disc mounted rotationally to the outer end of said spindle for rotation relative to said spindle to suitable sight position, means for fixing the disc, in its chosen sight position, to the spindle to rotate therewith, and reference pointer means adju'stably carried by said mounting base for adjustment to zero indexing position for the disc and cooperable with said timing disc to enable quick and accurate engine timing.

5. A timing assembly for engines for use with an auxiliary drive where direct access to the engine crankshaft is not readily available comprising a base plate, biased adapter means secured to the base plate for biased engagement with the auxiliary drive housing, a spindle journalled in said base plate and having the inner end thereof adapted for securing engagement with the auxiliary drive for rotation therewith, flange means connected to said spindle to prevent axial displacement thereof relative to said base plate, indexing means including a ring member concentric with one of said flange means and rotatable relative thereto, an arm integrally extending from said ring member, and reference pointer means on the outer extremity of said arm, said indexing means being rotatively adjustable about said spindle into suitable viewing position for the pointer means, means to fix the indexing means, in its adjusted position, to the base plate, a timing disc freely mounted on said spindle for rotative adjustment to zero setting with respect to the pointer means, and means to fix the disc to the spindle for rotation therewith and relative to said reference pointer means whereby engine timing may readily obtain.

6. An engine timing tool for attachment to a housed auxiliary unit such as a magneto or the like embodying an engine-driven shaft, said tool comprising a base plate, a spindle journaled in the base plate, indicating means for cyclic operational data and including a pair of coacting indicating elements rotatably engaged with the spindle for adjustment at will about said spindle to convenient viewing position and for adjustment relatively to each other to a zero setting, means to fix one of said indicating elements to the spindle for rotation therewith, means to fix the coacting indicating element to the base plate, the spindle having a socketed end to receive an end of the engine-driven shaft, said ends being constructed for direct drive coupling interconnection of the spindle and said shaft, and means for clamping the timing tool to the auxiliary unit, said clamping means comprising opposed jaws dependingly mounted on the base plate at diametrically opposite sides of the spindle for inwardly tensioned clamping engagement with the sides of the housing of said auxiliary unit to retain the spindle in coupled connection to the engine-driven shaft.

References Cited in the file of this patent V UNITED STATES PATENTS 2,090,020 Ballou Aug. 17, 1937 2,355,211 Erickson Aug. 8, 1944 2,437,283 Viers Mar. 9, 1948 2,664,012 Newsome Dec. 29, 1953 

